English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

This paper conceives a novel sparse code multiple access (SCMA) codebookdesign which is motivated by the strong need for providing ultra-low decodingcomplexity and good error performance in downlink Internet-of-things (IoT)networks, in which a massive number of low-end and low-cost IoT communicationdevices are served. By focusing on the typical Rician fading channels, weanalyze the pair-wise probability of superimposed SCMA codewords and thendeduce the design metrics for multi-dimensional constellation construction andsparse codebook optimization. For significant reduction of the decodingcomplexity, we advocate the key idea of projecting the multi-dimensionalconstellation elements to a few overlapped complex numbers in each dimension,called low projection (LP). An emerging modulation scheme, called golden anglemodulation (GAM), is considered for multi-stage LP optimization, where theresultant multi-dimensional constellation is called LP-GAM. Our analysis andsimulation results show the superiority of the proposed LP codebooks (LPCBs)including one-shot decoding convergence and excellent error rate performance.In particular, the proposed LPCBs lead to decoding complexity reduction by atleast $97\%$ compared to that of the conventional codebooks, whilst owninglarge minimum Euclidean distance. Some examples of the proposed LPCBs areavailable at \url{https://github.com/ethanlq/SCMA-codebook}.

A Design of Low-Projection SCMA Codebooks for Ultra-Low Decoding Complexity in Downlink IoT Networks